scholarly journals Intracellular transport and storage of secretory proteins in relation to cytodifferentiation in neoplastic pancreatic acinar cells.

1983 ◽  
Vol 96 (4) ◽  
pp. 949-960 ◽  
Author(s):  
M J Becich ◽  
M Bendayan ◽  
J K Reddy
Keyword(s):  
Golgi Apparatus ◽  
Secretory Granule ◽  
Intracellular Transport ◽  
Secretory Granules ◽  
Acinar Cells ◽  
Pancreatic Acinar Cells ◽  
Secretory Process ◽  
Secretory Proteins ◽  
Neoplastic Cells ◽  
Golgi Vesicles

The pancreatic acinar carcinoma established in rat by Reddy and Rao (1977, Science 198:78-80) demonstrates heterogeneity of cytodifferentiation ranging from cells containing abundant well-developed secretory granules to those with virtually none. We examined the synthesis intracellular transport and storage of secretory proteins in secretory granule-enriched (GEF) and secretory granule-deficient (GDF) subpopulations of neoplastic acinar cells separable by Percoll gradient centrifugation, to determine the secretory process in cells with distinctly different cytodifferentiation. The cells pulse-labeled with [3H]leucine for 3 min and chase incubated for up to 4 h were analyzed by quantitative electron microscope autoradiography. In GEF neoplastic cells, the results of grain counts and relative grain density estimates establish that the label moves successively from rough endoplasmic reticulum (RER) leads to the Golgi apparatus leads to post-Golgi vesicles (vacuoles or immature granules) leads to mature secretory granules, in a manner reminiscent of the secretory process in normal pancreatic acinar cells. The presence of approximately 40% of the label in association with secretory granules at 4 h postpulse indicates that GEF neoplastic cells retain (acquire) the essential regulatory controls of the secretory process. In GDF neoplastic acinar cells the drainage of label from RER is slower, but the peak label of approximately 20% in the Golgi apparatus is reached relatively rapidly (10 min postpulse). The movement of label from the Golgi to the post-Golgi vesicles is evident; further delineation of the secretory process in GDF neoplastic cells, however, was not possible due to lack of secretory granule differentiation. The movement of label from RER leads to the Golgi apparatus leads to the post-Golgi vesicles suggests that GDF neoplastic cells also synthesize secretory proteins, but to a lesser extent than the GEF cells. The reason(s) for the inability of GDF cells to concentrate and store exportable proteins remain to be elucidated.

scholarly journals Electron Microscopic Evidence Suggesting Secretory Granule Formation within the Golgi Apparatus

1957 ◽  
Vol 3 (2) ◽  
pp. 319-322 ◽  
Author(s):  
Marilyn G. Farquhar ◽  
S. Robert Wellings
Keyword(s):  
Golgi Apparatus ◽  
Secretory Granule ◽  
Secretory Granules ◽  
Acinar Cells ◽  
Secretory Activity ◽  
Pancreatic Acinar Cells ◽  
Electron Microscopic ◽  
Granule Formation ◽  
Golgi Bodies ◽  
Rat Pituitary

Secretory granules have been seen within components of the Golgi bodies of rat pituitary acidophils and mouse pancreatic acinar cells. The fact that secretory granules are much more frequently encountered within Golgi components under conditions of increased secretory activity suggests that granule formation may occur within the Golgi apparatus in these two types of cells.

scholarly journals Relationship between the golgi apparatus, gerl, and secretory granules in acinar cells of the rat exorbital lacrimal gland

1977 ◽  
Vol 74 (2) ◽  
pp. 399-413 ◽  
Author(s):  
AR Hand ◽  
C Oliver
Keyword(s):  
Endoplasmic Reticulum ◽  
Electron Microscope ◽  
Golgi Apparatus ◽  
Lacrimal Gland ◽  
Secretory Granules ◽  
Acinar Cells ◽  
Secretory Proteins ◽  
Thiamine Pyrophosphatase ◽  
Variable Distance ◽  
Secretory Enzyme

The method of secretory granuleformation in the acinar cells of the rat exorbital lacrimal gland was studied by electron microscope morphological and cytochemical techniques. Immature secretory granules at the inner face of the Golgi apparatus were frequently attached to a narrow cisternal structure similar to GERL as described in neurons by Novikoff et al. (Novikoff, P. M., A. B. Novikoff, N. Quintana, and J.-J. Hauw. 1971. J. Cell Bio. 50:859-886). In the lacrimal gland. GERL was located adjacent to the inner Golgi saccule, or separated from it by a variable distance. Portions of GERL were often closely paralleled by modified cisternae of rough endoplasmic reticulum (RER), which lacked ribosomes on the surface adjacent to GERL. Diaminobenzidine reaction product of the secretory enzyme peroxidase was localized in the cisternae of the nuclear envelope, RER, peripheral Golgi vesicles, Golgi saccules, and immature and mature secretory granules. GERL was usually free of peroxidase reaction product or contained only a small amount. Thiamine pyrophosphatase reaction product was present in two to four inner Golgi saccules; occasionally, the innermost saccule was dilated and fenestrated, and contained less reaction product than the next adjacent saccule. Acid phosphatase (AcPase) reaction product was present in GERL, immature granules, and, rarely, in the innermost saccule, but not in the rest of the Golgi saccules. Thick sections of AcPase preparations viewed at 100 kV revealed that GERL consisted of cisternal, and fenestrated or tublular portions. The immature granules were attached to GERL by multiple connections to the tublular portions. These results suggest that, in the rat exorbital lacrimal gland, the Golgi saccules participate in the transport of secretory proteins, and that GERL is involved in the formation of secretory granules.

scholarly journals RADIOAUTOGRAPHIC ANALYSIS OF THE SECRETORY PROCESS IN THE PAROTID ACINAR CELL OF THE RABBIT

1972 ◽  
Vol 53 (2) ◽  
pp. 290-311 ◽  
Author(s):  
J. David Castle ◽  
James D. Jamieson ◽  
George E. Palade
Keyword(s):  
Intracellular Transport ◽  
Secretory Granules ◽  
Close Association ◽  
Low Frequency ◽  
Secretory Process ◽  
Secretory Proteins ◽  
Surgical Removal ◽  
Storage Granules ◽  
And Storage

Intracellular transport of secretory proteins has been studied in the parotid to examine this process in an exocrine gland other than the pancreas and to explore a possible source of less degraded membranes than obtainable from the latter gland. Rabbit parotids were chosen on the basis of size (2–2.5 g per animal), ease of surgical removal, and amylase concentration. Sites of synthesis, rates of intracellular transport, and sites of packaging and storage of newly synthesized secretory proteins were determined radioautographically by using an in vitro system of dissected lobules capable of linear amino acid incorporation for 10 hr with satisfactory preservation of cellular fine structure. Adequate fixation of the tissue with minimal binding of unincorporated labeled amino acids was obtained by using 10% formaldehyde-0.175 M phosphate buffer (pH 7.2) as primary fixative. Pulse labeling with leucine-3H, followed by a chase incubation, showed that the label is initially located (chase: 1–6 min) over the rough endoplasmic reticulum (RER) and subsequently moves as a wave through the Golgi complex (chase: 16–36 min), condensing vacuoles (chase: 36–56 min), immature granules (chase: 56–116 min), and finally mature storage granules (chase: 116–356 min). Distinguishing features of the parotid transport apparatus are: low frequency of RER-Golgi transitional elements, close association of condensing vacuoles with the exit side of Golgi stacks, and recognizable immature secretory granules. Intracelular processing of secretory proteins is similar to that already found in the pancreas, except that the rate is slower and the storage is more prolonged.

scholarly journals Immunohistochemical localization of pancreatic exocrine enzymes in normal and neoplastic pancreatic acinar epithelium of rat.

1981 ◽  
Vol 29 (2) ◽  
pp. 309-313 ◽  
Author(s):  
L J Hansen ◽  
M Mangkornkanok/Mark ◽  
J K Reddy
Keyword(s):  
Secretory Granules ◽  
Acinar Cells ◽  
Immunohistochemical Localization ◽  
Model Systems ◽  
Secretory Process ◽  
Secretory Proteins ◽  
Variable Extent ◽  
Immunofluorescent Technique ◽  
Pancreatic Exocrine ◽  
Indirect Immunofluorescent

The transplantable pancreatic acinar carcinomas of rat established recently provide useful model systems to examine the composition of secretory proteins as well as the secretory process in transformed pancreatic exocrine epithelium. The neoplastic acinar cells exhibit considerable variation in the extent of cytodifferentiation. In the present study the enzymatic profile of this heterogeneous tumor cell population has been investigated by the indirect immunofluorescent technique using antibodies against six pancreatic enzymes. By immunofluorescence, all neoplastic cells stained positively for the six enzymes tested: amylase, lipase, carboxypeptidase A, chymotrypsinogen, trypsinogen, and ribonuclease. Some variability in the intensity of immunofluorescence was noted, suggesting possible quantitative differences in the content of a given enzyme among tumor cells. These observations suggest that neoplastic acinar cells with or without secretory granules contain secretory proteins, but to a variable extent.

Molecular chaperones in pancreatic tissue: the presence of cpn10, cpn60 and hsp70 in distinct compartments along the secretory pathway of the acinar cells

1994 ◽  
Vol 107 (3) ◽  
pp. 539-549 ◽  
Author(s):  
C.S. Velez-Granell ◽  
A.E. Arias ◽  
J.A. Torres-Ruiz ◽  
M. Bendayan
Keyword(s):  
Endoplasmic Reticulum ◽  
Golgi Apparatus ◽  
Secretory Pathway ◽  
Secretory Granules ◽  
Acinar Cells ◽  
Pancreatic Tissue ◽  
Secretory Proteins ◽  
Trans Golgi Network ◽  
Hsp70 Protein ◽  
Golgi Network

Three chaperones, the chaperonins cpn10 and cpn60, and the hsp70 protein, were revealed by immunochemistry and cytochemistry in pancreatic rat acinar cells. Western immunoblotting analysis of rat pancreas homogenates has shown that antibodies against cpn10, cpn60 and hsp70 protein recognize single protein bands of 25 kDa, 60 kDa and 70 kDa, respectively. Single bands for the cpn10 and cpn60 were also detected in pancreatic juice. Immunofluorescence studies on rat pancreatic tissue revealed a strong positive signal in the apical region of the acinar cells for cpn10 and cpn60, while an immunoreaction was detected at the juxtanuclear Golgi region with the anti-hsp70 antibody. Immunocytochemical gold labeling confirmed the presence of these three chaperones in distinct cell compartments of pancreatic acinar cells. Chaperonin 10 and cpn60 were located in the endoplasmic reticulum, Golgi apparatus, condensing vacuoles and secretory granules. Interestingly, the labeling for both cpn10 and cpn60 followed the increasing concentration gradient of secretory proteins along the RER-Golgi-granule secretory pathway. On the contrary, the labeling for hsp70 was mainly concentrated in the endoplasmic reticulum and the Golgi apparatus. In the latter, the hsp70 was found to be primary located in the trans-most cisternae and to colocalize with acid phosphatase in the trans-Golgi network. The three chaperones were also present in mitochondria. In view of the role played by the chaperones in the proper folding, sorting and aggregation of proteins, we postulate that hsp70 assists the adequate sorting and packaging of proteins from the ER to the trans-Golgi network while cpn10 and cpn60 play key roles in the proper packaging and aggregation of secretory proteins as well as, most probably, in the prevention of early enzyme activation in secretory granules.

scholarly journals DYNAMICS OF CYTOPLASMIC MEMBRANES IN GUINEA PIG PANCREATIC ACINAR CELLS

1974 ◽  
Vol 61 (1) ◽  
pp. 1-13 ◽  
Author(s):  
J. Meldolesi
Keyword(s):  
Molecular Weight ◽  
Membrane Proteins ◽  
Guinea Pig ◽  
Intracellular Transport ◽  
Sodium Dodecyl ◽  
Acinar Cells ◽  
Pancreatic Acinar Cells ◽  
Secretory Proteins ◽  
Zymogen Granule ◽  
Double Labeling

The rate of synthesis and the turnover of cytoplasmic membrane proteins were determined in the acinar cells of guinea pig pancreas with the aim of investigating the mechanisms by which the intracellular transport of secretion products occurs. These cells are highly specialized toward protein secretion. By means of in vitro pulse-chase experiments and in vivo double-labeling experiments, using radioactive L-leucine as the tracer, it was found that the turnover of secretory proteins is much faster than that of all membranes involved in their transport (rough and smooth microsome and zymogen granule membranes). Sodium dodecyl sulfate-polyacrylamide disk gel electrophoresis of membrane proteins revealed that in each of these membranes there is a marked heterogeneity of turnover; generally the high molecular weight polypeptides have a shorter half-life than the low molecular weight polypeptides. These data indicate that the membranes participating in the intracellular transport of secretory proteins are not synthesized concomitantly with the latter. Rather, they are probably reutilized in several successive secretory cycles. The possible relevance of these findings to other secretory systems is discussed.

CYTOTOXIC EFFECTS OF PUROMYCIN ON THE GOLGI APPARATUS OF PANCREATIC ACINAR CELLS, HEPATOCYTES AND AMELOBLASTS

1970 ◽  
Vol 18 (12) ◽  
pp. 875-886 ◽  
Author(s):  
ALFRED WEINSTOCK
Keyword(s):  
Protein Synthesis ◽  
Golgi Apparatus ◽  
Single Injection ◽  
Secretory Granules ◽  
Acinar Cells ◽  
Secretory Protein ◽  
Pancreatic Acinar Cells ◽  
Cytotoxic Effects ◽  
Total Inhibition

A single injection of puromycin was given to rats in a dose sufficient to produce almost total inhibition of protein synthesis in pancreas and liver. By 10 min after injection, Golgi saccules in pancreatic acinar cells, hepatocytes and ameloblasts appeared grossly and irregularly distended, and almost devoid of content. In pancreas the condensing vacuoles near the inner face of the Golgi were often altered, and those normally present in ameloblasts were lacking. Between 2 and 3 hr after injection, protein synthesis had started anew. At this time, granules without limiting membranes appeared within cisternae of the rough endoplasmic reticulum in acinar cells and ameloblasts. These intracisternal granules are believed to consist of newly synthesized secretory protein which could not be transported through the disrupted Golgi apparatus to be packaged into secretory granules. Indeed, by 3 hr postinjection the secretory granules which normally abound in the apical processes of ameloblasts were sparce or absent. Thus, while biochemical evidence indicates that puromycin blocks protein synthesis on the ribosomes, the use of this antibiotic in vivo results in alterations in the Golgi apparatus and interruption of the packaging of protein into secretory granules.

Membranes and membrane surfaces: Dynamics of cytoplasmic membranes in pancreatic acinar cells

1974 ◽  
Vol 268 (891) ◽  
pp. 39-53 ◽  
Keyword(s):  
Intracellular Transport ◽  
Polyacrylamide Gel Electrophoresis ◽  
Acinar Cells ◽  
Pancreatic Acinar Cells ◽  
Secretory Proteins ◽  
Turnover Rates ◽  
Membrane Surfaces ◽  
Random Fashion ◽  
In Series

In pancreatic acinar cells the intracellular transport of secretory proteins occurs through the inter-connexion of distinct membrane-bounded compartments: in series, the rough surfaced endoplasmic reticulum (r.e.r.), the Golgi complex (g.c.) and the secretory (zymogen) granules (z.g.). The latter organelles are able to fuse their membrane with the plasmalemma (pm.) and discharge their content by exocytosis. In order to investigate the mechanisms by which the intracellular transport occurs we have investigated the composition as well as the rate of synthesis and turnover of the various membranes involved in the process. We found that these membranes have distinct differences in chemical composition and in the distribution of enzyme activities and that their rate of turnover is much slower than that of secretory proteins. Furthermore, SDS polyacrylamide gel electrophoresis of doubly labelled membrane proteins revealed that in each of these membranes there is a marked heterogeneity of turnover rates. These data indicate ( a ) that the membranes participating in the intracellular transport interact with one another in a non-random fashion, ( b ) that they are not synthesized concomitantly with the secretion products, ( c ) that membranes are synthesized independently from one another, and ( d ) that they are re-utilized in several secretory cycles. Consistent with these results, a model explaining the role of cellular membranes in protein secretion is described. It is proposed that the intracellular transport is effected through the specific non-random interaction (fusion-fission) and recycling of the various participating membranes. The possible relevance of these findings to other secretory systems is discussed.

scholarly journals Redistribution of a rab3-like GTP-binding protein from secretory granules to the Golgi complex in pancreatic acinar cells during regulated exocytosis

1994 ◽  
Vol 124 (1) ◽  
pp. 43-53 ◽  
Author(s):  
BP Jena ◽  
FD Gumkowski ◽  
EM Konieczko ◽  
GF von Mollard ◽  
R Jahn ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Golgi Complex ◽  
Binding Protein ◽  
Secretory Granules ◽  
Acinar Cells ◽  
Pancreatic Acinar Cells ◽  
Apical Plasma Membrane ◽  
Gtp Binding Protein ◽  
Regulated Exocytosis ◽  
Gtp Binding

Regulated secretion from pancreatic acinar cells occurs by exocytosis of zymogen granules (ZG) at the apical plasmalemma. ZGs originate from the TGN and undergo prolonged maturation and condensation. After exocytosis, the zymogen granule membrane (ZGM) is retrieved from the plasma membrane and ultimately reaches the TGN. In this study, we analyzed the fate of a low M(r) GTP-binding protein during induced exocytosis and membrane retrieval using immunoblots as well as light and electron microscopic immunocytochemistry. This 27-kD protein, identified by a monoclonal antibody that recognizes rab3A and B, may be a novel rab3 isoform. In resting acinar cells, the rab3-like protein was detected primarily on the cytoplasmic face of ZGs, with little labeling of the Golgi complex and no significant labeling of the apical plasmalemma or any other intracellular membranes. Stimulation of pancreatic lobules in vitro by carbamylcholine for 15 min, resulted in massive exocytosis that led to a near doubling of the area of the apical plasma membrane. However, no relocation of the rab3-like protein to the apical plasmalemma was seen. After 3 h of induced exocytosis, during which time approximately 90% of the ZGs is released, the rab3-like protein appeared to translocate to small vesicles and newly forming secretory granules in the TGN. No significant increase of the rab3-like protein was found in the cytosolic fraction at any time during stimulation. Since the protein is not detected on the apical plasmalemma after stimulation, we conclude that recycling may involve a membrane dissociation-association cycle that accompanies regulated exocytosis.

scholarly journals Golgi apparatus, GERL, and secretory granule formation within neurons of the hypothalamo-neurohypophysial system of control and hyperosmotically stressed mice.

1981 ◽  
Vol 90 (2) ◽  
pp. 474-484 ◽  
Author(s):  
R D Broadwell ◽  
C Oliver
Keyword(s):  
Golgi Apparatus ◽  
Secretory Granule ◽  
Supraoptic Nucleus ◽  
Salt Water ◽  
Secretory Granules ◽  
Hyperosmotic Stress ◽  
Granule Formation ◽  
Smooth Membrane ◽  
Secondary Lysosomes ◽  
The Relationship

The vasopressin-producing neurons of the hypothalamo-neurohypophysial system are a particularly good model with which to consider the relationship between the Golgi apparatus nd GERL and their roles in secretory granule production because these neurons increase their synthesis and secretion of vasopressin in response to hyperosmotic stress. Enzyme cytochemical techniques for acid phosphatase (AcPase) and thiamine pyrophosphatase (TPPase) activities were used to distinguish GERL from the Golgi apparatus in cell bodies of the supraoptic nucleus from normal mice, mice hyperosmotically stressed by drinking 2% salt water, and mice allowed to recover for 5-10 d from hyperosmotic stress. In nonincubated preparations of control supraoptic perikarya, immature secretory granules at the trans face of the Golgi apparatus were frequently attached to a narrow, smooth membrane cisterna identified as GERL. Secretory granules were occasionally seen attached to Golgi saccules. TPPase activity was present in one or two of the trans Golgi saccules; AcPase activity appeared in GERL and attached immature secretory granules, rarely in the trans Golgi saccules, and in secondary lysosomes. As a result of hyperosmotic stress, the Golgi apparatus hypertrophied, and secretory granules formed from all Golgi saccules and GERL. Little or no AcPase activity could be demonstrated in GERL, whereas all Golgi saccules and GERL-like cisternae were TPPase positive. During recovery, AcPase activity in GERL returned to normal; however, the elevated TPPase activity and secretory granule formation seen in GERL-like cisternae and all Golgi saccules during hyperosmotic stress persisted. These results suggest that under normal conditions GERL is the predominant site for the secretory granule formation, but during hyperosmotic stress, the Golgi saccules assume increased importance in this function. The observed cytochemical modulations in Golgi saccules and GERL suggest that GERL is structurally and functionally related to the Golgi saccules.

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